Supersymmetric model for dark matter and baryogenesis motivated by the recent CDMS result.

We discuss a supersymmetric model for cogenesis of dark and baryonic matter where the dark matter (DM) has mass in the 8-10 GeV range as indicated by several direct detection searches, including most recently the CDMS experiment with the desired cross section. The DM candidate is a real scalar field. Two key distinguishing features of the model are the following: (i) in contrast with the conventional weakly interacting massive particle dark matter scenarios where thermal freeze-out is responsible for the observed relic density, our model uses nonthermal production of dark matter after reheating of the Universe caused by moduli decay at temperatures below the QCD phase transition, a feature which alleviates the relic overabundance problem caused by small annihilation cross section of light DM particles and (ii) baryogenesis occurs also at similar low temperatures from the decay of TeV scale mediator particles arising from moduli decay.

Unifying inflation and dark matter with neutrino masses.

We propose a simple model where a gauge-invariant inflaton is responsible for cosmic inflation and generates the seed for structure formation, while its relic thermal abundance explains the missing matter of the Universe in the form of cold dark matter. The inflaton self-coupling also explains the observed neutrino masses. All the virtues can be attained in a minimal extension of the standard model gauge group around the TeV scale.

Gauge-invariant inflaton in the minimal supersymmetric standard model.

We argue that all the necessary ingredients for successful inflation are present in the flat directions of the Minimally Supersymmetric Standard Model. We show that out of many gauge-invariant combinations of squarks, sleptons, and Higgs bosons, there are two directions, LLe and udd, which are promising candidates for the inflaton. The model predicts more than 10(3) e-foldings, with an inflationary scale of H(inf) approximately O(1-10) GeV, provides a tilted spectrum with an amplitude of delta(H) approximately 10(-5) and a negligible tensor perturbation.

Production of massive stable particles in inflaton decay.

We point out that inflaton decays can be a copious source of stable or long-lived particles chi with mass exceeding the reheat temperature T(R) but less than half the inflaton mass. Once higher order processes are included, this statement is true for any chi particle with renormalizable (gauge or Yukawa) interactions. This contribution to the chi density often exceeds the contribution from thermal chi production, leading to significantly stronger constraints on model parameters than those resulting from thermal chi production alone, particularly in models containing stable charged particles.